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![Nicholas Piggin](/assets/img/avatar_default.png)
This function builds the cores online map with on-stack cpumasks which can cause high stack usage with large NR_CPUS. It is not used in any performance sensitive paths, so instead just check for first thread sibling. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Tested-by: Sachin Sant <sachinp@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20211105035042.1398309-1-npiggin@gmail.com
115 lines
2.8 KiB
C
115 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_CPUTHREADS_H
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#define _ASM_POWERPC_CPUTHREADS_H
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#ifndef __ASSEMBLY__
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#include <linux/cpumask.h>
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#include <asm/cpu_has_feature.h>
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/*
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* Mapping of threads to cores
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*
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* Note: This implementation is limited to a power of 2 number of
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* threads per core and the same number for each core in the system
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* (though it would work if some processors had less threads as long
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* as the CPU numbers are still allocated, just not brought online).
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*
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* However, the API allows for a different implementation in the future
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* if needed, as long as you only use the functions and not the variables
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* directly.
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*/
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#ifdef CONFIG_SMP
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extern int threads_per_core;
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extern int threads_per_subcore;
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extern int threads_shift;
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extern cpumask_t threads_core_mask;
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#else
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#define threads_per_core 1
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#define threads_per_subcore 1
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#define threads_shift 0
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#define has_big_cores 0
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#define threads_core_mask (*get_cpu_mask(0))
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#endif
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static inline int cpu_nr_cores(void)
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{
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return nr_cpu_ids >> threads_shift;
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}
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#ifdef CONFIG_SMP
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int cpu_core_index_of_thread(int cpu);
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int cpu_first_thread_of_core(int core);
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#else
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static inline int cpu_core_index_of_thread(int cpu) { return cpu; }
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static inline int cpu_first_thread_of_core(int core) { return core; }
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#endif
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static inline int cpu_thread_in_core(int cpu)
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{
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return cpu & (threads_per_core - 1);
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}
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static inline int cpu_thread_in_subcore(int cpu)
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{
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return cpu & (threads_per_subcore - 1);
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}
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static inline int cpu_first_thread_sibling(int cpu)
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{
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return cpu & ~(threads_per_core - 1);
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}
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static inline int cpu_last_thread_sibling(int cpu)
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{
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return cpu | (threads_per_core - 1);
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}
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/*
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* tlb_thread_siblings are siblings which share a TLB. This is not
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* architected, is not something a hypervisor could emulate and a future
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* CPU may change behaviour even in compat mode, so this should only be
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* used on PowerNV, and only with care.
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*/
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static inline int cpu_first_tlb_thread_sibling(int cpu)
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{
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if (cpu_has_feature(CPU_FTR_ARCH_300) && (threads_per_core == 8))
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return cpu & ~0x6; /* Big Core */
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else
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return cpu_first_thread_sibling(cpu);
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}
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static inline int cpu_last_tlb_thread_sibling(int cpu)
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{
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if (cpu_has_feature(CPU_FTR_ARCH_300) && (threads_per_core == 8))
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return cpu | 0x6; /* Big Core */
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else
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return cpu_last_thread_sibling(cpu);
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}
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static inline int cpu_tlb_thread_sibling_step(void)
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{
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if (cpu_has_feature(CPU_FTR_ARCH_300) && (threads_per_core == 8))
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return 2; /* Big Core */
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else
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return 1;
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}
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static inline u32 get_tensr(void)
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{
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#ifdef CONFIG_BOOKE
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if (cpu_has_feature(CPU_FTR_SMT))
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return mfspr(SPRN_TENSR);
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#endif
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return 1;
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}
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void book3e_start_thread(int thread, unsigned long addr);
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void book3e_stop_thread(int thread);
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#endif /* __ASSEMBLY__ */
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#define INVALID_THREAD_HWID 0x0fff
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#endif /* _ASM_POWERPC_CPUTHREADS_H */
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